Airbag apparatus for automobile

Abstract

An airbag apparatus utilizes an interior panel of a vehicle. The interior panel has a rectangular fracture-opening section defined by at least one hinge groove and one fracture groove formed on an inside surface of the interior panel through irradiation with laser pulses. The fracture groove includes bridge portions and continuous hole portions provided alternately. Each of the bridge portions includes no laser-formed hole and has a thickness equal to the interior panel. Each of the continuous hole portions is composed of first holes for fracture which have a first depth and are successively formed between adjacent bridge portions through irradiation with laser pulses, and second holes which have a second depth smaller than the first depth and are each formed between adjacent first holes, through irradiation with laser pulses, so as to remove an original-thickness portion between the adjacent first holes.

1. An airbag apparatus for an automobile, comprising an airbag disposed in a folded condition behind an interior panel at a predetermined position, the interior panel having a generally rectangular fracture-opening section at a position corresponding to that of the airbag, the fracture-opening section being defined by at least one hinge groove and one fracture groove generally parallel to the hinge groove, the hinge groove and fracture groove being formed on an inside surface of the interior panel through irradiation with laser pulses, the fracture-opening section being opened toward two opposite directions or a single direction when the airbag is expanded and deployed, wherein
 the fracture groove includes bridge portions and continuous hole portions provided alternately, each of the bridge portions including no laser-formed hole and having a thickness equal to the interior panel, each of the continuous hole portions being composed of first holes for fracture which have a first depth and are successively formed between adjacent bridge portions through irradiation with laser pulses, and second holes which have a second depth smaller than the first depth and are each formed between adjacent first holes, through irradiation with laser pulses, so as to remove an original-thickness portion between the adjacent first holes. 
 
     
     
       2. An airbag apparatus for an automobile according to  claim 1 , wherein
 the interior panel is formed of a single-layer sheet; 
 the fracture-opening section is defined by front and rear hinge grooves, a center fracture groove generally parallel to the hinge grooves, and left and right fracture grooves generally perpendicular to the hinge grooves; 
 when the airbag is expanded and deployed, the fracture-opening section is split at the center fracture groove into front and rear fracture-opening subsections which are opened toward two opposite directions; and 
 the center fracture groove includes bridge portions and continuous hole portions provided alternately, each of the bridge portions including no laser-formed hole and having a thickness equal to the interior panel, each of the continuous hole portions being composed of first holes for fracture which have a first depth and are successively formed between adjacent bridge portions through irradiation with laser pulses, and second holes which have a second depth smaller than the first depth and are each formed between adjacent first holes, through irradiation with laser pulses, so as to remove an original-thickness portion between the adjacent first holes. 
 
     
     
       3. An airbag apparatus for an automobile according to  claim 2 , wherein each of the hinge grooves is formed of holes successively formed on the inside surface of the interior panel through irradiation with laser pulses and has a depth about half the thickness of the interior panel; each of the left and right fracture grooves is formed of holes successively formed on the inside surface of the interior panel through irradiation with laser pulses and has a depth for reaching a position near the outer surface of the interior panel, and the first holes of the center fracture groove have a depth for reaching a position near the outer surface of the interior panel. 
     
     
       4. An airbag apparatus for an automobile according to  claim 1 , wherein
 the interior panel is formed of a single-layer sheet; 
 the fracture-opening section is defined by a rear hinge groove, a front fracture groove generally parallel to the hinge groove, and left and right fracture grooves generally perpendicular to the hinge groove and the front fracture groove; 
 when the airbag is expanded and deployed, the fracture-opening section is fractured and opened toward a single direction; and 
 the front fracture groove includes bridge portions and continuous hole portions provided alternately, each of the bridge portions including no laser-formed hole and having a thickness equal to the interior panel, each of the continuous hole portions being composed of first holes for fracture which have a first depth and are successively formed between adjacent bridge portions through irradiation with laser pulses, and second holes which have a second depth smaller than the first depth and are each formed between adjacent first holes, through irradiation with laser pulses, so as to remove an original-thickness portion between the adjacent first holes. 
 
     
     
       5. An airbag apparatus for an automobile according to  claim 4 , wherein the hinge groove is formed of holes successively formed on the inside surface of the interior panel through irradiation with laser pulses and has a depth about half the thickness of the interior panel; each of the left and right fracture grooves is formed of holes successively formed on the inside surface of the interior panel through irradiation with laser pulses and has a depth for reaching a position near the outer surface of the interior panel, and the first holes of the front fracture groove have a depth for reaching a position near the outer surface of the interior panel. 
     
     
       6. An airbag apparatus for an automobile according to  claim 1 , further comprising a rectangular reinforcement frame member for reinforcing a portion of the interior panel surrounding the fracture-opening section, wherein the reinforcement frame member has a reinforcement edge portion formed around an upper opening thereof, and elongated projections formed on an upper surface of the reinforcement edge portion, whereby the rectangular reinforcement frame member is fixed to the inside surface of the interior panel via the elongated projections by means of vibration welding. 
     
     
       7. An airbag apparatus for an automobile according to  claim 6 , wherein the reinforcement frame member has an elongated burr prevention flange which is formed at the upper opening thereof and slightly projects toward the center of the opening. 
     
     
       8. An airbag apparatus for an automobile according to  claim 6 , wherein each of the interior panel and the reinforcement frame member is formed of a thermoplastic orefinic elastomer (TPO).